The high water absorption rate not only greatly reduces the mechanical properties and electrical properties of PA6 materials, but also seriously affects the dimensional stability of the parts. PA6 modification reduces the water absorption rate is one of the important topics.
Molecular structure of PA6
At present, there are three types of methods for reducing water absorption by modifying PA6:
1, adding blending modification aids (such as LLDP, PP, maleic anhydride grafting, etc.);
2, adding inorganic filler additives (such as: calcium carbonate, talcum powder, etc.);
3, surface modification.
PA6 modified slice
What is the principle or the focus of PA6 modified water absorption?
There are roughly three things:
1, the polarity of the shielding effect
By adding a filler, it reacts with polar amide groups, terminal amino groups, and carboxyl groups that absorb water easily in the PA6 molecular chain, shielding it, and the water absorption rate is significantly reduced.
2, the shielding effect of the crystal area
PA6 is a semi-crystalline material, water molecules can easily enter the amorphous region with large polar groups. The fillers and blended modified materials effectively improve the crystallinity of PA6 modified materials, not only improve the mechanical properties, but also increase the water absorption. It will also drop significantly.
3, the shielding effect of the structure
Among PA6 modified materials, PA6 material is a continuous phase, and the filler or surface treatment agent is a dispersed phase. The phase interface between the two is strong, and the non-polar long chain of the filler or blend material effectively blocks the PA6 material and water molecules. The contact, so the water absorption rate decreased significantly.